class User{
	//User(this.name,this.age);//简写常规构造函数
	//User(String name,int age){
		//常规构造函数；
		//this.name = name;
		//this.age = age;
	//}
	
	
	User.fromtoJson(map json){
		String name;
		int age;
		name = json['name'];
		age = json['age'];
	}
}

main(){
	var user = new User();
	
}